Method of treating fluorine compounds and treated substance

Abstract

Divalent and trivalent metal salts are added to the solution containing the fluorine compound to precipitate the layered double hydroxide containing the fluorine compound between layers. By these processes, the fluorine compound can be fixed with high rate. Moreover, if necessary, the precipitated layered double hydroxide can be recovered to separate the fluorine compound or its salt between layers. Therefore, the burden to environment or the ecosystem by the fluorine compound can be reduced.

1. A layered double hydroxide of formula (I),
   M(II) 1-x M(III) x (OH) 2 Y x/m ·nH 2 O  (I) 
 
       wherein, Y is an anion of an organic fluorine compound having a fluorocarbon chain, and a valence number of m,
 M(II) is a divalent metal ion, 
 M(III) is a trivalent metal ion, 
 X is 0.1 to 0.5, and 
 n is a positive integer, 
 wherein the layered double hydroxide is a solid obtained by
 adding one or more divalent and trivalent metal salts to a solution comprising the organic fluorine compound having a fluorocarbon chain to precipitate the layered double hydroxide wherein the layered double hydroxide has the fluorine compound present between layers, and 
 separating the precipitate by solid-liquid separation. 
 
 
     
     
       2. The hydroxide according to  claim 1 , wherein, M(II) is a divalent ion of Mg or Ca, and M(III) is a trivalent ion of Al or Fe. 
     
     
       3. The hydroxide according to  claim 1 , wherein Y is an anion of a carboxylic acid or sulfonic acid having a fluorocarbon chain having more than 5 carbon atoms. 
     
     
       4. The hydroxide according to  claim 1 , wherein the hydroxide is a resource to reuse the fluorine compound. 
     
     
       5. The hydroxide according to  claim 1 , wherein X=⅓, m=1, and the formula of the hydroxide is:
   M(II) 2 M(III)(OH) 6 Y·nH 2 O. 
 
     
     
       6. The hydroxide according to  claim 5 ,
 wherein, M(II) is a divalent ion of Mg or Ca, and M(III) is a trivalent ion of Al or Fe. 
 
     
     
       7. The hydroxide according to  claim 5 , wherein Y is an anion of a carboxylic acid or a sulfonic acid having a fluorocarbon chain having more than 5 carbon atoms. 
     
     
       8. The hydroxide according to  claim 5 ,
 wherein the hydroxide is a resource to reuse the fluorine compound.